It is desirable that charging systems for electric and/or hybrid vehicles accommodate delivery of high power over wide range of operating input/output voltages, while at the same time achieving galvanic isolation, unity power factor, low harmonic distortion, high power density and low cost. Many charging systems employ a two power stage design. The first power stage includes a wide input voltage range unity power factor boost converter that provides an output voltage higher than the voltage of the energy source being charged. The second stage provides galvanic isolation and processes the voltage and current to an acceptable level for the energy source being charged. However, using two power stages is inefficient (e.g., in terms of component size, power consumption, and cost) and inflexible, that is, the two power stage charging systems often accommodate a particular combination of voltages for the two energy sources.